feat(fase2): wire Step-1 ExpeL retrieval into the hypothesis prompt

Closes maalbilde §5 gap #1 (the one missing "feedback-into-prompt" dataflow)
for the OKF-bundle path. Before, ExpeL was computed AFTER generation into a
discarded SessionContext, so a prior verdict could not influence any hypothesis
(context_providers=0).

- New okf.py: framework-neutral OKF bundle navigation (index + frontmatter +
  cross-links), pure stdlib, no agent_framework/mcp (D7-portable), enforced by
  test_okf_is_maf_free.
- verdicts.py: seed_store_from_bundle + bundle_candidate_features build the
  ExpeL substrate + the pre-hypothesis query key from a bundle.
- run_project(bundle_dir=...): folds the candidate's prior verdicts into the
  generation context BEFORE generate_via_llm; the road path is unchanged.

Load-bearing (maalbilde §7): test_step1_expel_loadbearing proves a prior verdict
reaches the hypothesis prompt and goes RED when the fold is detached (shown via
TDD red->green). The marker is the minted verdict id (content hash) because
docs_dir==bundle_dir lets keyword chunk-stuffing leak the realization rate;
clean layer separation is Fase 2b.

Suite 121->133 passed; mypy + ruff check clean.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MHR8iKxJRxDiDfNw8HZmWE

tests/test_okf.py

@@ -0,0 +1,96 @@
+"""OKF bundle navigation (okf.py) — the framework-neutral, D7-portable context seam.
+
+These tests pin the minimal navigation the Step-1 ExpeL wiring depends on: read ``index.md``,
+follow intra-bundle cross-links, parse each file's frontmatter, classify by ``type``, and locate
+the candidate IR projection. Robustness (OKF SPEC §4): broken links are tolerated, never raised.
+
+No ``agent_framework``/``mcp`` import is allowed in ``okf`` — guarded by ``test_okf_is_maf_free``.
+"""
+
+from __future__ import annotations
+
+from pathlib import Path
+
+from portfolio_optimiser import okf
+
+BUNDLE_DIR = Path(__file__).resolve().parents[1] / "shared" / "examples" / "bygg-energi-mikro"
+
+
+def test_navigate_classifies_every_typed_file() -> None:
+    """The energi bundle resolves to its six typed OKF files (index + project + hypothesis +
+    methodology + reference + verdict), each carrying its declared ``type``."""
+    bundle = okf.navigate_bundle(str(BUNDLE_DIR))
+    types = {f.name: f.type for f in bundle.files}
+    assert types == {
+        "index.md": "index",
+        "bygg-kontor-nord.md": "project",
+        "tiltak-led-retrofit.md": "hypothesis",
+        "metode-ipmvp-a.md": "methodology",
+        "kilder-realiseringsgap.md": "reference",
+        "verdict-led-fro.md": "verdict",
+    }
+
+
+def test_navigate_exposes_verdicts_and_hypothesis() -> None:
+    """The navigation surfaces exactly one ``type: verdict`` file (the ExpeL seed) and the
+    candidate hypothesis — the two the Step-1 wiring keys on."""
+    bundle = okf.navigate_bundle(str(BUNDLE_DIR))
+    assert [f.name for f in bundle.verdicts] == ["verdict-led-fro.md"]
+    assert bundle.verdicts[0].frontmatter["realization_rate"] == "0.82"
+    assert bundle.hypothesis is not None
+    assert bundle.hypothesis.name == "tiltak-led-retrofit.md"
+
+
+def test_navigate_index_summary_is_progressive_disclosure() -> None:
+    """``index_summary`` is the index body (the progressive-disclosure entry point), not stuffing
+    the whole bundle."""
+    bundle = okf.navigate_bundle(str(BUNDLE_DIR))
+    assert "progressiv disclosure" in bundle.index_summary.lower()
+
+
+def test_navigate_tolerates_broken_links(tmp_path) -> None:
+    """OKF SPEC §4: a consumer MUST tolerate broken links. An index linking a missing file
+    navigates without raising, simply omitting the absent target."""
+    (tmp_path / "index.md").write_text(
+        "---\ntype: index\n---\n\nSee [gone](missing.md) and [here](real.md).\n",
+        encoding="utf-8",
+    )
+    (tmp_path / "real.md").write_text("---\ntype: project\n---\n\nbody\n", encoding="utf-8")
+    bundle = okf.navigate_bundle(str(tmp_path))
+    names = {f.name for f in bundle.files}
+    assert names == {"index.md", "real.md"}  # missing.md silently skipped, no raise
+
+
+def test_load_ir_projection_returns_candidate_ir() -> None:
+    """The bundle's IR projection (``validator-input.json``) is the candidate measure's cost-IR —
+    the pre-hypothesis ExpeL query key source."""
+    ir = okf.load_ir_projection(str(BUNDLE_DIR))
+    assert ir["project_id"] == "BYGG-KONTOR-NORD"
+    assert [a["code"] for a in ir["affected_items"]] == ["ENERGI-TOTAL-EL"]
+    assert ir["claimed_saving_nok"] == 30000
+
+
+def test_parse_frontmatter_reads_scalar_fields() -> None:
+    """The minimal frontmatter reader returns the leading ``---`` block as key:value strings."""
+    fm = okf.parse_frontmatter(BUNDLE_DIR / "verdict-led-fro.md")
+    assert fm["type"] == "verdict"
+    assert fm["decision"] == "approved_with_adjustment"
+
+
+def test_okf_is_maf_free() -> None:
+    """D7 portability: ``okf.py`` IMPORTS no ``agent_framework`` / ``mcp`` (the docstring may name
+    them to document the constraint, exactly as ``retrieval.py`` does) — checked via the AST, not a
+    raw substring, so the prose claim doesn't trip the guard."""
+    import ast
+
+    src = (
+        Path(__file__).resolve().parents[1] / "src" / "portfolio_optimiser" / "okf.py"
+    ).read_text(encoding="utf-8")
+    imported: list[str] = []
+    for node in ast.walk(ast.parse(src)):
+        if isinstance(node, ast.Import):
+            imported += [a.name for a in node.names]
+        elif isinstance(node, ast.ImportFrom):
+            imported.append(node.module or "")
+    forbidden = [m for m in imported if m.split(".")[0] in {"agent_framework", "mcp"}]
+    assert forbidden == [], f"okf.py must not import MAF/mcp, found: {forbidden}"